Hi everyone. I unexpectedly won an Okuma Integrity 8/9 fly reel online and realized (oh geez) for about $10 more, I could have picked up a 5/6. I live in Oklahoma and we have a variety of species. Is the 8/9 size too large for smaller species like Crappie, Bluegill or Trout or can I use it as an all-purpose reel if I use different rods and lines?

Yes, it is too large. But, that doesn't mean it couldn't be used in a pinch. The 5/6 would have been much more suitable. Other than appearing too large on the rod and weighing quite a bit more than what might be comfortable IF you use it with a rod suitable for those species, it can be made to work. An 8/9 weight reel on an 8/9 weight rod would balance and cast OK, but would be total overkill for the species you listed. That would be better suited for freshwater stripers and largemouth bass fishing in your area.